Before that please mention either the values of correlation coefficients or the confidence levels of these correlations.

In case of groundwater, arsenic concentration varies with different aquifer dissolution from Fe and Mn complexes and different lithologic compositions might play an important role in correlation between Fe and Mn towards As in groundwater. Please go through the below given article (sorry for the inconvenience as the article is in two parts) where it has been stated clearly with evidence-

Arnab Majumdar beat me to the punch. I was going to refer to the paper cited in his reply.

Arnab , Appreciated your appropriate response.

It is possible and depends upon the speciation of elements in water at any given physico-chemical conditions. Perform Phreeqci modelling (freely available at USGS website) and you can check how these elements behaves in your samples.

Elevated contents of arsenic in the ground- and surface water in India and Bangladesh are the result of a geogen process caused by oscillating redox conditions in one of the strongest tidal regimes on the globe the impact of which can be recognized for quite a long distance landward of the coastline. Arsenic has it primary host in Fe sulfides such as pyrite, marcasite, pyrrhotite, bravoite (Ni pyrite) and greigite. These chemical compounds rank among the most widespread minerals and they are very redox –sensitive. One of the most common oxidic As minerals is scorodite known as a hydrated iron arsenate mineral, with the chemical formula FeAsO4·2H2O. There is no equivalent system for Mn which rarely exists as MnS (alabandine). Moreover in the oxidizing regime bivalent Fe and Mn show strongly different stability fields with FeOOH (goethite, lepidocrocite) being very common and MnOOH (manganite) being rather rare. It goes without saying that dependent upon the redox regime Mn and Fe follow up various pathways of evolution particularly during the supergene alteration under near ambient conditions. And as a consequence of this the chemical relationship of iron and manganese (which has more valence states than iron) breaks apart under oxidizing conditions. Arsenic in the arsenate complex is more common to “limonite” than “manganomelane”. It can be present in a loosely-bound way absorbed to these poorly crystalline compounds of “limonite” or present as a true arsenate. This is not the case with equivalent Mn compounds.

H.G.Dill